Rotary lapping machine



Sept. 11, 1956 s. E. FRANKLIN 2,762,172

ROTARY LAPPING MACHINE Filed Dec. 15, 1953 IN V EN TOR.

STANLEY E. FRANKLIN F55. Z.

ATTOP/VE).

United States Patent assignor to Califi, a corporation This inventionrelates to new and useful improvements in rotary lapping machines andhas particular reference to such a machine which is relatively simpleand economical in construction yet rugged and accurate and wherein theWorking plate may be maintained flat without recourse to otherequipment.

An object of the invention is to provide a new and improved rotarylapping machine which is relatively simple, rugged and inexpensive inconstruction and eX- tremely accurate.

Another object is to provide a rotary lapping machine of the type setforth wherein the use of mated plates and a plurality of plates,preferably three, progressively lapped together and with a minimum ofcare maintains working surfaces of optical flatness.

Another object is to provide a new and improved rotary lapping machineof the type set forth with means for recording the total running timeand also, automatically, whereby the timing of operation of the devicemay be controlled.

Another object is to provide new and improved rotating guides for arotary lapping machine.

Other objects and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanyingdrawings. It will be understood that changes may be made in the detailsof construction and arrangement of parts without departing from thespirit of the invention as set forth in the accompanying claim, as thepreferred form has been given by way of illustration only.

Referring to the drawings:

Fig. 1 is a top or plan view of a rotary lapping machine constructedaccording to the invention; and

Fig. 2 is a front view, partly in section, of the apparatus shown inFig. 1.

Referring more particularly to the drawings wherein similar referencecharacters designate corresponding parts throughout, the apparatus showncomprises the housing in which is contained the lapping plate driveassembly 11 adapted to be driven by the motor 12 through the pulleys 13and 14 and belt 15.

Above the upper surface of the housing 10 is positioned the lappingplate 16 which is mounted on the drive shaft 17 which is journaled inthe support 18 and which has the beveled gear 19 secured thereon by thepin 20.

Pulley 14 is mounted on drive shaft 21 on which is positioned piniongear 22 which meshes with beveled gear 19 for driving the same.

The timing device 23 is provided for indicating the total hours ofoperation and may be utilized to aid in determining when the lappingplates need relapping and to help determine production costs.

The timing control mechanism 24 contains an on and off switch forturning the machine on and off, and timing mechanism which allowsoperation of the device for a predetermined desired period, such as onehour, without the necessity of attention of the apparatus and thenautomatically shuts oif the apparatus.

Adjacent the lapping plate 16 is provided a plurality, preferably apair, of supports 25 on each of which is adjustably mounted a bracket orlocating arm 26 which is retained on the stud 27 on the support 25 bymeans of the wing nut 28.

Each of the brackets 26 has a buffer or guide or rotary support 29 on ashaft 30 and mounted for revolution relative to its respective bracket26.

Each rotary lapping machine is provided with three lapping plates 16which are preferably spiral grooved fine cast iron plates having thespiral grooves 31 in the lapping surfaces which grooves are charged withsuitable grinding or lapping material. By providing three such plateswith each machine, the plates are mated and progressively lappedtogether and therefore each of the plates will, with a minimum of care,maintain a working surface of optical flatness and thereby any wear onthe existing working plate can be lapped out.

The locating arms 26 rotating support or fixtures 29 are adapted forautomatic operation of the device and thereby allowing the adaptation toautomatic operation of what would otherwise be numerous slow and tedioushand lapping operation and thereby results in the saving of time and theincrease of the quality of the lapped surface produced. The locatingarms are adjusted by loosening of wing nuts 23 and then moving thelocating arms until the members or guides 29 are in engagement withedges of the work and the wing nuts 28 are then tightened. By thismeans, when the lapping plate 16 is rotated the work is automaticallyrotating on the lapping plate during the lapping operation.

The operation of the apparatus is believed apparent from the foregoingdescription.

From the foregoing it will be seen that I have provided simple,economical and efiicient means for obtaining all of the objects andadvantages of the invention.

I claim:

In a rotary lapping machine, a support, a lapping plate mounted on saidsupport and adapted to support a Work piece, said lapping plate having aspiral groove in its working surface with abrasive material filling saidspiral groove, means for rotating said lapping plate comprising aspindle on which said plate is concentrically mounted, a bevel gear onsaid spindle, a motor, and means including said bevel gear operativelyconnecting said motor to said spindle, two separate relatively movablelocating arms pivotally mounted on said frame at spaced points foradjustment in a plane parallel to and over said lapping plate, a guiderotatably mounted on each of said arms and adapted to engage the edgesof a single Work piece so that rotation of said work piece will beeifected by rotation of said lapping plate, control means including anautomatic timing device and an automatic switch for controlling saidmotor whereby the machine may be operated for a predetermined period oftime without attention by the operator, and an indicating means forindicating the total time of operation of the machine so that theoperator is advised of the need for resurfacing the lapping plate.

References Cited in the file of this patent UNITED STATES PATENTS494,471 Gardner Mar. 28, 1893 537,971 Fuller Apr. 23, 1895 1,230,717Kalteyer June 19, 1917 1,517,293 Keim Dec. 2, 1924 1,735,599 CrowleyNov. 12, 1929 1,926,974 Einstein Sept. 12, 1933 2,255,583 Holland Sept.9, 1941 2,275,061 Indge Mar. 3, 1942 2,405,344 Cloutier Aug. 6, 19462,627,144 Roshong Feb. 3, 1953

